Field of the Invention
The present invention relates to an actuator device which drives a flight control surface of an aircraft.
Description of the Related Art
In aircrafts, a hydraulically-operated actuator is generally used for driving an aileron, an elevator, and a rudder that constitute a control surface. The hydraulic actuator supplies hydraulic oil from a hydraulic source provided on an aircraft fuselage side to thereby drive the flight control surface such as the aileron. To ensure reliability for the aircrafts, a hydraulic system which uses at least two actuators, and supplies hydraulic oil to the respective actuators from flow paths of separate systems has been proposed (e.g., Japanese Patent Laid-Open No. 2012-116466). In the hydraulic system, even when the function of one of the systems including the actuators is lost or reduced, the system is switched to the other system so as to drive the flight control surface.
As shown in FIG. 6B, in a case in which the hydraulic system includes two actuators (a first actuator 131A and a second actuator 131B), the first actuator 131A and the second actuator 131B are suspended between a main wing 2 and an aileron body 11. In the first actuator 131A, a piston rod 132A is connected to the aileron body 11 via a connection fitting 141A. In the second actuator 131B, a piston rod 132B is connected to the aileron body 11 via a connection fitting 141B.
During normal cruising, the first actuator 131A is used to drive the flight control surface (e.g., the aileron body 11). At this point, the second actuator 131B stands by so as to ensure redundancy. The second actuator 131B acts as a damper for the operation of the first actuator 131A during standing by. For example, as shown in FIG. 6B, when the piston rod 132A of the first actuator 131A is extended, a pushing force P acts on the aileron body 11, and a tensile force T acts on a portion to which the second actuator 131B is connected. Accordingly, a shear stress or a torsional stress is generated between the connection fitting 141A of the first actuator 131A and the connection fitting 141B of the second actuator 131B in the aileron body 11. When the stress S is repeatedly applied, fatigue of the portion of the aileron body 11 is accelerated.
It is thus an object of the present invention to provide an actuator device which drives a flight control surface, and can reduce a stress generated on the flight control surface when one actuator out of at least two actuators is operated.